Our wireless motion sensor is completely portable and ready to guard any area you choose. It monitors the surroundings and announces visitors by creating an unseen barrier that's almost impossible to penetrate without setting off the alarm. Simply mount the unit on a table or wall so it focuses on the detection area. When the Sensor Guard is in the monitoring position, any detected motion will activate a pleasant doorbell-sounding chime. When switched to the alarm setting, any detected motion will sound an 80 dB alarm. Sensor has a 26-foot (8 meter) range. Includes wall/ceiling mount plate with bracket. Easy-to-use, no wiring required, battery operated, uses three AA alkaline batteries (sold separately).